Graph with no options takes pairs of numbers from the standard
input as abscissas (x–values) and ordinates (y–values) of a graph.
Successive points are connected by straight lines. The graph is
encoded on the standard output for display by plot(1) filters.

If an ordinate is followed by a nonnumeric string, that string
is printed as a label beginning on the point. Labels may be surrounded
with quotes " " in which case they may be empty or contain blanks
and numbers; labels never contain newlines.

The following options are recognized, each as a separate argument.
–a Supply abscissas automatically; no x–values appear in the input.
Spacing is given by the next argument (default 1). A second optional
argument is the starting point for automatic abscissas (default
0, or 1 with a log scale in x, or the lower limit given by –x).
–b Break (disconnect) the graph after each label in the input.
–c Character string given by next argument is default label for
each point.
–g Next argument is grid style, 0 no grid, 1 frame with ticks, 2
full grid (default).
–l Next argument is a legend to title the graph. Grid ranges are
automatically printed as part of the title unless a –s option is
present.
–m Next argument is mode (style) of connecting lines: 0 disconnected,
1 connected. Some devices give distinguishable line styles for
other small integers. Mode –1 (default) begins with style 1 and
rotates styles for successive curves under option –o.
–o (Overlay.) The ordinates for n superposed curves appear in the
input with each abscissa value. The next argument is n.
–p Next argument is one or more of the characters bcgkmrwy, choosing
pen colors by their initial letter, as in plot(6). Successive
curves will cycle through the colors in the given order.
–s Save screen; no new page for this graph.
–x lIf l is present, x–axis is logarithmic. Next 1 (or 2) arguments
are lower (and upper) x limits. Third argument, if present, is
grid spacing on x axis. Normally these quantities are determined
automatically.
–y lSimilarly for y.
–e Make automatically determined x and y scales equal.
–h Next argument is fraction of space for height.
–w Similarly for width.
–r Next argument is fraction of space to move right before plotting.
–u Similarly to move up before plotting.
–t Transpose horizontal and vertical axes. (Option –a now applies
to the vertical axis.)

If a specified lower limit exceeds the upper limit, the axis is
reversed.